Quote:a crossbreed is the F1 cross of 2 different strain of chickens, he will be heterozygous for all of his parents original Non sexual chromozomes.....so if you cross the heterozigous brothers you´ll end up with a bunch of possible combinations....check this link, its Mendel´s second law http://biology.about.com/library/weekly/aa110603a.htm

Theoretically it is possible, but the reality of having all the genes line up correctly seems pretty slim.

Let's assume you have two birds who are identical in every way except gender. Since they are crossbreeds, some/many of the genes will be heterozygous. For each heterozygous gene you'll end up with 25% pure for allele1, 50& het for the two alleles and 25% pure for allele2. Now if you could get the correct pure alleles to line up for every gene, you'd have a genetic purebred. However chances of getting the 33 genes covered in the chicken calculator, not to mention all the other ones that aren't there or aren't well documented to line up correctly? I'd lay a very large amount of cash against it, and give you odds. (If I was a betting woman, which I'm not.)